They probably won't retro fit for a while.
And I think it's a little early to declare the seats extremely perfect given no real customers have flown them yet.
I was upgraded to PEY on my flight from Bangkok to Hongkong in A350 a few months back. The seat was very nice, with leg extender for all, better TV screen and control etc. From now on, given a choice, I would pick the PEY A350 instead of the old seats on 777.